Concepts for flexible and efficient monochromatization of X-rays by refraction to a relative bandwidth of the order of 0.5%

Recently it was shown experimentally that regular arrays of tiny prisms can be used as X-ray monochromators providing a spectral bandwidth of below 2%. Successively the measured spectral transmission functions of monochromators operated under different conditions were found to be in agreement with expectations within an analytical model. This type of monochromator focuses chromatically and thus necessitates the use of an exit slit for the monochromatization. This contribution will show that the lower limit for the achievable bandpass can be predicted under practically feasible experimental conditions. Refractive monochromators based on prism arrays are found to be feasible solutions for monochromatization with high transmission to a spectral bandwidth of the order of 0.5%. The bandwidth can easily be increased by adjusting the exit slit setting accordingly. Consequently, the presented refractive devices would make for tunable monochromators with tunable bandwidth, which provides more flexibility for an intermediate bandwidth of <1%, which multilayer monochromators have difficulty providing routinely.